Led Display Circuit - Toshiba e-studio550 Service Manual

5. 4. 2. LED display circuit

(1) Method of LED display
ex) Displaying "COPY"
LDON0
The transistor is turned ON when the LDON 0 signal becomes "L" level.
Also, when IC8-17pin (D7) changes to "L", the current flows from 5VL via the transistor to LED4 ("COPY")
to turn ON LED4 ("COPY").
Conditions to turn ON the LED
(a) The transistor (Q3) connected to the LED anode is ON.
(b) The output from the cathode side of the LED is "L" level.
The LED is turned ON when (a) and (b) are satisfied.
e-STUDIO550/650/810 CONTROL PANEL
5VL
"L"
Q3
Current
"L" 17
G
R3
(COPY)
LED4
IC8(7932)
5 - 10
D7
JUNE 2002 © TOSHIBA TEC